The present patent application claims the benefit of earlier Japanese Patent Application Nos. 2000-77052 and 2000-297505 filed Mar. 17, 2000 and Sep. 28, 2000, respectively, the disclosures of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a clip for tightly holding two or more sheet-like materials, such as an automobile body panel and an interior trim. More specifically, the invention relates to a clip, in which a grommet and a pin are coupled via hinges into a single unit, thereby greatly reducing forces required to push the grommet and the pin into a hole.
2. Description of the Related Art
A conventional single-unit clip used to hold two panels or the like is disclosed by, for example, Japanese Patent No. 2796850. FIG. 1 illustrates the conventional clip, which is inserted into a hole (not shown) formed in an automobile panel to hold a trim or a liner against the panel. The inserted clip catches the edges of the hole, thereby securely holding two materials together.
The conventional clip 1 illustrated in FIG. 1 includes a grommet 2 having a V-shaped cross-section in the free state, a pin 3 placed in the grommet 2 and movable in the axial direction, and a pair of hinges for coupling the pin 3 with the grommet 2. The hinges 5 extend from the tip of the pin 3 obliquely downward to the V-shaped elastic leg 6 of the grommet 2 so as to have an inverse V-shaped cross-sectional view before the clip is inserted in the hole.
When inserting the clip 1 into the hole, the side of the grommet 2 is held between fingers and pressed inward so that the grommet 2 is easily inserted in the hole. After the insertion, the grommet 2 expands in the radial direction by its own elastic force and returns to its original states. As a result, the barrel 7 of the grommet 2, which is made thicker than the leg 6, comes into tight contact with the edges of the hole for receiving the clip. Then, the head 8 of the pin 3 is depressed in the direction of the arrow, and the spindle 4 of the pin 3 is inserted into the valley of the V-shaped elastic leg 6 against the elastic force of the hinges 5.
If the pin 3 is further depressed, the barrel 7 expands in the radial direction, and the annular projection 4a of the spindle 4 gets over the step 9 formed in the inner wall of the grommet 2. In this state, the grommet 2 and the pin 3 are engaged with each other, and the clip is firmly fixed into the hole of the panel.
However, with the conventional clip 1, the hinges 5 coupling the spindle 4 of the pin 3 to the grommet 2 are arranged in the same plane in which the V-shaped leg 6 extends. In addition, the hinges 5 extend from the middle portion of the V-shaped leg 6 to the tip of the spindle 4. For these reasons, the lengths of the hinges 5 inevitably become short if the grommet 2 is made small in size. As the hinge 5 becomes shorter, the rigidity of the hinge 5 increases, which causes a high reaction against the insertion of the pin 3. Consequently, an increased amount of load is required to push the pin 3 into the grommet 2. In order to this disadvantage, the length of the hinge 5 must be sufficiently long, which prevents the clip 1 to be made compact.
Another problem in the conventional clip 1 is that if the increased rigidity of the hinge 5 of a smaller-sized clip limits the freedom of selecting a material for the hinge 5. Due to the rigidity of the hinge 5, only those materials that have adequate flexibility and elasticity can be used so as not to cause the hinge 5 to break. If a soft material is used, the mechanical strength of the clip is insufficient. Conversely, if a hard synthetic resin is used for purposes of increasing the strengths of the grommet 2 and the pin 3, which is required to securely fix the clip into the hole, then, the clip is easy to break.
The invention was conceived to overcome these problems in the prior art technique. Therefore, it is one of the objectives of the invention to provide an improved clip structure, which can reduce the load applied to the clip during the insertion of the clip, while preventing the hinges from breaking. This clip structure is especially effective if the clip is small-sized, or if the hinge is made of a hard material for purposes of guaranteeing a secure hold.
The clip of the present invention is a single-unit clip, in which the grommet and the pin are coupled with each other via hinges. The clip comprises a grommet having a V-shaped leg portion, a pin that is movable in the axial direction in the valley of the V-shaped leg portion, and a pair of hinges for coupling the pin with the grommet. The hinges extend in planes not parallel to the plane defined by the V-shaped leg portion of the grommet. Preferably, the hinges extend in planes perpendicular to the plane defined by the V-shaped leg portion.
The hinges are curved in its free state before the clip is actually used, in order to guarantee a sufficient length and flexibility.
The hinges may be twisted in alternate directions in planes no parallel to the plane defined by the V-shaped leg portion. In this case, each hinge couples the pin with a middle portion of an edge of the associated leg pieces of the V-shaped leg.
The grommet has a pair of half barrels extending from top ends of the V-shaped leg and facing each other, and a pair of flanges extending horizontally from top end of the half barrels. Each of the half barrels has a protrusion in its inner face, and grooves are formed on the pin. The protrusions of the half barrels are fit into the grooves of the pin when the pin is pushed into the V-shaped leg of the grommet.
The grommet has a pair of semicircular flanges, and bridges for coupling both ends of each semicircular flange with the pin. In this case, the bridges are cut off if the pin is pushed into the grommet due to a shear stress.
Preferably, grommet, the pin, and the hinges are monolithically formed using a polyacetal resin.
In another aspect of the invention, a clip comprises a grommet having a V-shaped leg portion, a pin movable in the axial direction in a space between the V-shaped leg, and a pair of curved hinges coupling the pin with the V-shaped leg portion of the grommet. In this case, the curved hinges may be arranged in planes parallel to the plane defined by the V-shaped leg portion in an alternate manner.
In still another aspect of the invention, a clip comprises a grommet having a V-shaped leg portion, a pin being movable in the axial direction in a space between the V-shaped leg, and a single curved hinge coupling the pin with the V-shaped leg of the grommet.
The hinge is shaped in, for example, an S-shape. The longitudinal axis of the curved or the S-shaped hinge extends in a plane perpendicular to the plane defined by the longitudinal axes of the V-shaped leg portion.